Fuse



Patented'Novj. 2, l

2,433,101 ori-nca FUSE John cfomcm, wcshmmn, n. c., and Brama H. Tabl, Jr., Arlington, Va.

Application September 1, 1944. Serial No. 5525352 l s claim. (ci. 1oz-ve) (Granted under the act of March. 3, 1883, as

The invention described herein may be manufactured and used by'or for the Government for governmental purposes', without the payment to l The general object of our invention is to pro'- ,vide a fuze for a projectile which may be red from a gun in unarmed or safe" position, but

. which will become armed after the projectile leaves the muzzle of the gun, the time of arming from the time of discharge being regulated or controlled by the design of the fuze elements.

Afurther object of our invention is to provide a device of this character in which temperature controlled means are utilized in maintaining the fuze in unarmed position and in which the employment of heat is utilized to function the ternperature controlled means in order to permit the withdrawal of a safety device and in which centrifugal force rotates the firing pin to a position in alignment with a detonator assembly,.which assembly is adjacent to a flash passage leading to an explosive charge.

A still further object of our invention is to provide a device of this character utilizing an inertia element, which will extend the usefulness of the inertia type of fuze to guns in such a condition of wear in which the present type of inertia fuze may `not be used, due to the fact that the fuze may function prematurely.

A still further object of our invention is to provide a fuze of this character which increases protection against premature functioning by failure of metal parts which might permit the firing pin to penetrate the primer of the detonator assembly and in which fewer and'simpler parts are employed, and in which the number of critical dimension of the various parts are less than those of the fuzes now being used.

A 'still further object of our invention is to provide a fuze of this character in-which no parts with small surfaces which might fail and cause premature functioning or failure to function are employed and in which the possibility of assembling the fuze without lall of the parts is minimized.v

A still further object of our invention is to provide a fuze of this character Vwhich is safe to handle. which is economical to manufacture and which may be readily and quickly assembled.

partly broken With these and other objects in view, as will A hereafter more fully appear and which will be more particularly pointed out in the appended claims, reference is now made to the accompanying drawings forming a part of this application, in which:

Figure 1 is a vertical, longitudinal section of amended Aprll. 1928; 370 0. G. 757) our improved fuze Vmountedy in a portion of a projectile, with the firing pin carrier for the rotor in locked, unarmed position:

Figure 2 is a vertical, .longitudlnal section of the fuze, at right angle to theview o1' Fig. l, showing the fuze in armed position;

Figure 3 is a transverse, vertical sectional view, away', taken on the line 3--3- of Figure 4 is also a transverse, vertical sectional view, taken on the line 4 4 of Fig. 2;

Figure 5 is also a transverse, vertical sectional view, taken on the line 5 5 of Fig. l; and

Figure 6 is a detail view of the rotor lock pin cover, a b imetallic thermostatic element, utilized in our fuze.

It is well recognized in the art that the use of an inertia element is necessary in a fuse if the fuze is to function when the projectile is fired for graze impact, or upon ricochet action. The need for such functioning is a definite tactical require'. ment and it is apparent that if the inertia eiement is sensitive enough to function upon ricochet action, the projectile must be quite stable in its flight and the useful life of guns firing the type of inertia fuzes now in use is much less than in firing other types of fuzes, for the reason that as soon as the projectile becomes slightly unstable, due to worn riing in the gun, there is danger of premature functioning of the fuze and projectile, either in the bore of the gun, or so near to the muzzle after leaving thel gun, that it is unsafe as well as undesirable.

The delayed arming feature of our new fuze permits the projectile to recover from any initial instability before becoming armed, hence preventing premature functioning of the fuze and projectile, regardless of whether or not the riiiing in the gun has become worn. Delayed arming is preferable to placing an intcrrupter in the rear of'the fuze, or placing a, delayed arming mechanism in the booster, for the reason that should the fuze function, but be arrested by such devices, the projectile would not function later upon impact with the target. Delayed arming prevents premature functioning of the fuze, thereby insuring that it will be ready to function upon impact with the target.

Inthe fuze now being used, the design is such that the firing pin is directly over and in alignment with the primer ofthe delay element. When the -gun is fired, the ring pin is driven by natural forces toward the primer and the safety elcment therefore depends upon critical material and workmanship as well as correct assembly of all the parts, to prevent the functioning of the fuze in the gun, whereas by the use of our improved fuze. the ilring'pin is not directly over orin alignment with the primer until the fuze becomes armed, which setter the mojectileneagvestha with the fuze now in use. Furthermore. in theI fuze now in use, centrifugal pins and springs'are employed,- and if these are left out in assembling',

the fuze may function in transit, or while in the gun. In our improved fuze the rotor, containing the firing pin, can be assembled in only one cover 52 is moved to recess.

The front end of I6 is serrated as indicated at 6 and adapted to receive primer holder plate '50', which plate isy correspondingly serrated, as

l indicated at 8B. Plate EB is provided with an position and if it is not placed in the assembly,

the plunger body will go so far into the fuze body that it will be noticeable to the assembly operator who places the retaining ring into the' fuze body.

Referring now to the drawings, in: whichy similar reference characters represent similar parts, the numeral 2 designates -the fuze body, reduced at its rear end as indicated at 4 and threaded into the projectile 6 as usual.

Suitably secured to the fuze body is the ogive 8 that merges into the conventional fuze head, not shown. In the present instance, the head may contain a conventional firing pin and detonator assembly. which, however, forms no part of our aperture 62 through which flash tube' I0 is positoned. The platev is maintained in position by means of a threaded nut 64. Positioned centrally near one end ofl plate 58 is a conventional primer 68, in alignment with that portion of lock pin cover 52 adjacent the outer end of recess lhwhile a flexible striker member 6l is secured to the plate 68 by one of its ends in such a manner that the striker member is adapted to contact and initiate the primer upon the rin'g of the gun when setback or inertia force is applied. This ignition of the primer causes a discharge ot heat against the rotor lock pin cover 52. This'heat causes the b'imetal or thermo-metal cover to turn np, tending to coil forwardly and toward the head of screw a 554. This serves to release the rotor lock pin which invention and, therefore,A need not be 'shown or further b described. However, there is connected to this assembly a flash tube I0 provided with a bore I2 a part which is shown in Figs. 1 and 2. threaded at it rear end into the bore I4 of a boss I6, positioned centrally on the front end of the fuze body 2. The body 2 is provided with a small bore I8 forming a continuation of the bore I2 of flash tube I0.

The numeral designates the plunger body,

hereinafter referred to as the plunger. This plunger is slidably positioned in a recess 22 in the fuze body and is provided with a cylindrical bore 24 in axial alignment with bores I2 and I8. A'

and the forward end face of the recess 22 in the fuze body. The rotor is pivotally attached to the fuze body by a pivot pin 38, which pin extends considerably rearward of the rotor and into a socket 40 in the plunger, in which socket it has a working fit. The socket 40 is of a sufficient depth to permit the plunger 20 to move forward in the recess 22 sumciently for the firing pin 42, which is carried by the rotor 3 to contact the primer or detonator assembly 4 i, which assembly is ec' centrically mounted in t e fuze body, when the4 rotor is rocked to bring the firing pin 42 into vertical alignment with the detonator.

The rotor 36 has a recess 48 at its end opposite its pivot, adapted to receive a, rotor locking pin or safety member 4B, slidably mounted in an oblique aperture 50 in the front end of the fuze body 2. The inner end of this pin extends normally into the recess 46 locking the rotor against movement and thereby maintaining the fuse in un' armed position. l

The aperture 5U extends through the front of the fuze body and the outer end of the locking pin 48 positioned therein normally engages a bimetal or other thermally responsive rotor lock pin cover 52, which is securely held' in place on the front end of the fuze body by means of a conventional screw 64. This arrangement of parts prevents the escape of the rotor locking pin-46 from the recess 50 until such time as the lock pin will mo've outward along its axis, actuated by the resultant oi centrifugal and creep forces, thereby releasing the rotor, which, under the influence of centrifugal force, will rock to the armed position, shown in Figs. 2 'and 4, with the firing pin 42 .in alignment with the detonator assembly 44, which communicates with the main charge :hamber of the projectile by a ilash passage 44'.

In the fuze body. above the rotor and intersecting the bore l8,'is an interrupter 'luhaving an aperture 'l2 transversely therethrough, adapted to be brought by rotation of the interrupter into registry with said bore or not. according to whether the head portion is to be used in connection with a quick or delayed action fuze.

In operation, the fuze having been armed as described above, and assuming that the bore I8 be closed, as illustrated in Figs. 1 and 2,'and when the rotor has been rocked or rotated by centrifugal force until it is stopped by contact with the wall of the recess 22 in the fuze, body, at which point of stoppage it brings the firing pin in line withthe detonator assembly, when impact of the projectile occurs with a target, the plunger 2 0 moves-forward driving the detonator assembly `into contact with the firing pin, functioning the detonator and, successively, the explosive charge of the projectile. I

It will be apparent, of course, that the interrupter 'I0 may be set to unblock the bore I8 if desired, whereby the detonator assembly in the head of the shell may function to initiate the explosion of the shell on impact, in addition to the delayed arming detonator assembly carried by the plunger- It will also be apparent that the time interval between the firing of the shell from a gun and the operation-of the delayed arming mechanism may be varied and controlled, either by varying the charge and composition of the primer, or by varying the composition or thickness of the bimetal or other thermally responsive metal strip.

In the functioning of the device 52 as disclosed,

the transfer of heat from the products of burning of the primer 66 to the forward element of the bimetallic strip 52 is comparatively rapid but the transfer from this forward element to the rear velement of the strip involves a rate factor by retarded heat transfer which delays the necessary movement of the piece 52 (for clearance of the pin 48 from the rotor) until the projectile is well clear of the gun. 4The strip' 52 thus becomes a motive device or prime mover, independent of uncover the outer end of the f 4that the invention is not to be limited to such details, but only by the spirit. of the invention vand the scope of the appendedciaims.

We claim:

1. In a fuze for attachment to a shell containing an explosive charge, a delay arming mechanism comprising a body, a plunger mounted in said body and adapted for forward movement upon impact of said shell witha target, a rotor mounted on said body and carrying a firing pin, said rotor being proportionedand pivoted so as to be operable by centrifugal force and having a normal unarmed position blocking said plunger against movement, said rotor having an alternate armed position with the firing pin spaced before the plunger, a detonator assembly' mounted in the plunger aligned with the armed position of the firing pin, means responsive to theK movement of said shell upon being fired from al gun to unlock the rotor and to permit the rotor, under inuence of centrifugal force, to move to armed position with its firing pin in axial alignment with said detonator assembly to function said assembly upon the forward 'movement of said plunger.

2. In a fuze for attachment to a shell containing an explosive charge, a delay arming mechanism comprising a body, a plunger mounted in said body and adapted for forward movement upon impact of said shell l with a target, a rotor mounted in said body and carrying a ring piu.-

said rotor being proportioned and pivoted so as to be operable by centrifugal force and having a normal unarmed position blocking said plungerv against movement, said rotor' having an alternate armed position with the ring pin spaced before the plunger, a detonator assembly mountedin the plunger aligned with the armed position of the ring pin, heat actuated motive means to unlock the rotor, and means responsive to the` movement of said shell upon being iired from a gun constructed and arranged to communicate combustion products to said motive means, to unlock the rotor to permit the rotor, under influence of centrifugal force, to move to an armed position with its firing pin in axial alignment with I said detonator assembly to function said assembly upon the forward movement of said plunger.

3. In a fuze for attachment to a shell containing an explosive charge, a delay arming mechanism comprising a body, a recess in said body, a plunger mounted in said recess and adapted for forward movement upon impact of said shell with a target, a rotor pivotally mounted in said recess and carrying a firing pin, said rotor being operable by centrifugal force and normally blocking said plunger against movement. a detonator assembly mounted in said plunger eccentric to the 'axis thereof, locking means for locking said robly into contact with .said firing pin for functioning said assembly.

4. In a fuze for attachment to a shell contain-I ing an explosive charge, a delay arming mechanism comprising a body, a recessin said body, a

plunger mounted in said recess and adapted forV forward movement upon impact of said shell with a target, a rotor pivotally mounted in said recess and carryinga ringpin, said rotor being operable by centrifugal force and normally blocking said plunger against movement, a detonator assembly mounted in said plunger eccentric to the axis thereof, locking means for locking said rotor against rotation, a bi-metal strip adapted to retain said locking means in locked position, means for applying heat to said bi-metal strip, .whereby said locking means are unlocked, said means comprising a striker member and a primer functionally engageable responsive to movement of said shell upon being nred from a gun, means for rotating said rotor under inuence of centrifugal force to bring said firing pin in axial alignment with said detonator and to unblock forward movement of said plunger, whereby upon impact of said shell with a target said plunger will move forward to bring said detonator assembly into contact with said firing pin for functioning said assembly.

' `5. In a fuze for attachment to a shell contain` ingan explosive charge, a delay arming mechanism comprising a body, a recess in said body, a plunger mounted in said recess and adapted for forward movement upon impact of said shell with a target, a rotor pivotally mounted in said recess and carrying a iring pin, said rotor being operable by centrifugal force and normally blocking said plunger against movement, a detonator assembly mounted in said plunger eccentric to the axis thereof, an angularly disposed safety member slidably positioned in said body, said safety member engaging and blocking the rotation of said rotor, a heat responsive member constructed and mounted to move in response to augmented heat thereon from an initial unarmed position adapted to retain said safety membei` in engagement with said rotor to an armed position clear oi' said safety member, means for applying heat to said heatresponsive member, whereby said safety member disengages said rotor under the influenceV of centrifugal force, means responsive to the movement of said shell upon being red from a gun for rocking said rotor to bring said firing pin in axial augment with said detonator assembly and to unblock forward movement of 'said plunger, whereby upon impact of said shell with a target said plunger will move forward to bring said detonator assembly into contact with said firing pin for functioning said assembly.

JOI-IN C. GILLE'I'I'E. BRAXTON H. TABB, Jn.

REFERENCES crrEn The following references are of record in the ille of this patent:

UNITED STATES PATENTS 

